Study On The Valuable Component Separation Of High Aluminum Iron Ore Reinforced By Low Grade Manganese Iron Ore On Synergism

Aluminum is the second largest metal element after iron element in the world,and it is the basic raw material and strategic metal for the development of the national economy.China is the world’s largest producer and consumer of aluminum.However,China’s aluminum resources are heavily dependent on imports,and its dependence on foreign countries exceeds 50%.In order to ensure the safety and stable supply of China’s aluminum resources and realize the sustainable and healthy development of China’s economy,based on the characteristics of China’s aluminum resources,we can effectively use China’s aluminum resources and improve the comprehensive utilization level of aluminum resources.High iron bauxite is a kind of iron aluminum composite resource,in which the iron and aluminum grades are not up to the requirements of their respective industries,and the iron aluminum inlay is glued and closely symbiotic,which is difficult to be effectively separated by conventional methods.Metallic reduction and magnetic separation is considered to be more suitable for the treatment of complex refractory minerals.Traditional method needs to add sodium salt to effectively separate iron and aluminum.But a large amount of sodium salt makes it difficult to use iron.Therefore,it is hoped that the process of smelting can be developed by using available minerals instead of additives.China’s manganese ore resources are relatively scarce,most of which are low-grade manganese iron ore(abbreviated as LGMIO.Traditional smelting methods often have large investment and low recovery rates,failing to achieve large-scale industrial production.MnO in manganese ore can decrease the melting point of the slag phase and hinder the formation of iron-aluminum spinel to improve the reduction conditions.Therefore,a synergistic LGMIO enhanced HAIO valuable component separation and comprehensive utilization process is proposed.The process does not require the addition of other additives.The aluminum-rich manganese slag obtained by this process can be used as an industrial raw material for enriching aluminum and manganese,thereby achieving comprehensive utilization of resources.Based on this process,the basic characteristics of HAIO and LGMIO are first studied.Then,through thermodynamic calculations,the differences between individual reduction of HAIO and synergistic reduction of HAIO and LGMIO are compared in detail.Next,the phase transition of the reduction process is analyzed.The limiting part of the reduction process is discussed.And the metal particle growth process of the two reduction methods is analyzed and compared.An experimental study on the strengthening of reduction and magnetic separation of HAIO by adding LGMIO was conducted under laboratory conditons.The effects of factors such as ore powder ratio,reduction temperature,and reduction time on the reduction results are explored.The following conclusions are reached:(1)Iron-aluminum spinel FeAl2O4 will be formed during the reduction of HAIO,hindering the reduction of iron-containing phase.The critical reduction conditions are 831℃ and CO volume fraction 92%.MnO will replace part of FeO in Fe-Al spinel after adding LGMIO.Reducing the reduction conditions to 725℃ and CO volume fraction 62%,the reduction conditions have been greatly improved.(2)The reduction process of HAIO is similar to that of HAIO-LGMIO,and both are analyzed using porous material models.The two are divided into two stages with a certain critical reduction rate.The limiting link of both is the diffusion of gas through the reduced product layer of iron oxide particles(referred to as internal diffusion).The activation energy of HAIO in the first stage is 174 kJ/mol,and the activation energy of the second stage is 252 kJ/mol.The first stage activation energy of synergistic reduction of HAIO-LGMIO is 144 kJ/mol,and the second stage activation energy is 94 kJ/mol.At the same time,the rate equation is also calculated.(3)Under laboratory conditions,the suitable process parameters for strengthening of reduction and magnetic separation of HAIO by adding LGMIO are obtained:alumino-manganese mineral ratio 7/3,carbon-oxygen ratio 0.8,reduction temperature 1300℃,reduction time 90 min,Grinding time 5 min,magnetic field strength 100 mT.The iron recovery rate of this process reach 90.6%,the TFe and Mn content in the obtained magnetic product is 78.2%and 6.66%respectively.